Trivially, this result is clearly obvious.

I swear the only time I ever heard trivial in a lecture was once I got into university. It's a whole new ball game; high school teachers wouldn't dare say trivial just in case they had someone who was behind.

No it's not. i is a number such that i^2 = -1 by definition.

And in some contexts -1 is rotating by 180 degrees, which happens to be 290, or i*i.